3 ways to kill crabgrass for good

Crabgrass is a relentless yard invader. Wherever you live, you can shut out this grass trespasser and run barefoot through sweet success.

3 ways to kill crabgrass for good

It grows faster than turf, has incredible tolerance for adverse conditions and will quickly turn a lawn into a weed patch. Fortunately, you don't need to call a lawn service to rescue your grass.

1. Yank 'em while they're young!

Your lawn has been growing for a couple of months and you notice light green blades thickening up your Kentucky Blue. Before you think your lawn is having an exceptional season, think again: It's likely to be young crabgrass.

  • Pulling, at this early stage, is a surprisingly effective way to get rid of crabgrass. But if the weed has pushed up three or four rows of leaves, inspect it carefully before you snatch it.
  • If you spot a slender, green seed head that is still closed and folded up against the leaves of the plant, go ahead and pull it, too.
  • However, after the seed head tines have spread out like a fork, leave it alone. Otherwise you'll scatter scads of seeds right over that nice big hole you've just created by removing the mature weed. You might as well be trying to cultivate new crabgrass!
  • Come fall, seed bare and patchy areas. With good lawn care practices, you'll soon crowd out those fallen crabgrass seeds.

2. Spray stubborn patches

  • Spray post-emergence herbicide directly on crabgrass after it has sprouted.
  • Pulling is equally effective, but if the roots are deeply embedded in your lawn, it may be tough to pull them out without pulling grass chunks too. It's not worth spraying a post-emergence product on crabgrass that has gone to seed.
  • It takes about two weeks for the herbicide to work, which is about how long it takes the plant to finish its seeding process.
  • If it has gone to seed, you're better off waiting for next spring and applying a pre-emergence product then.
  • After post-emergence application(s), keep an eye on the treated area.
  • In extremely dry conditions, water two days after the application to aid absorption.
  • If the grass near the treated area is turning brown, you probably were a little heavy-handed.
  • Soak the damaged area with water to dilute the chemical and avoid further damage.
  • Also be on the lookout for new crabgrass sprouts. These will require another herbicide treatment, or if there aren't too many, simply pull them. Be sure to seed these areas in the fall.
  • Don't waste your money on a post-emergence herbicide in the fall, when the temperatures are falling. The herbicide won't be effective and the plant will soon die anyway.

3. Kill it all and start over!

While everyone admires those who relentlessly defend their turf against crabgrass, there comes a time when the best strategy is to give up. That time is when your lawn only has 30 to 40 per cent desirable grass left in a given area and the rest is lost to crabgrass and other weeds.

  • Begin by killing all the vegetation.
  • On a low-wind day, apply a non-selective herbicide approved for lawn use.
  • Follow the label directions exactly. Depending on the product, weeds and grass will die and dry up in 5 to 14 days following application. Then re-seeding can proceed.
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